Heat exchange apparatus



Feb. 5, 1935. I J POTTER 1,990,251

HEAT EXCHANGE APPARATUS Filed April 17, 1933 3 sheeis-sheet 1 ho Q Mg}?l? III wrmsgssas: m. m g INVENTOR 4M JOHN HPo'rTEFe. CLW M ATTORNEY Feb.5, 1935.

J.'A. POTTER 1,990,251 HEAT EXCHANGE APPARATUS Filed April 17, 1933 5Sheets-Sheet 2 w masses: 4M

i INVENTOR 6- I v JOHN APQTTER.

BY I Q,/5 flM-p4 ATTORNEY Feb. 5, 1935. J. A.YPOTTER 1,990,251

HEAT EXCHANGE APPARATUS 7 Filed April 17, 1933 y 3 Sheets-Sheet 3 vITNE'SSESI INVENIOR A v v JOHN HJ OTTER (2 0358 ATTORNEY Patented Feb.5, 1935 srss mica-51 Westinghouse Electric 8; Manufacturing Compa y,East Pittsburgh, Pa, a corporation of Pennsylvania Application April 17,1933, Serial No. 666,5 l

6 Claims.

My invention relates to heat exchange apparatus of the surface ortubular type, and more particularly to those wherein fluid circulatingtubes extend longitudinally through a tubular shell and connect a fixedheader construction closing one end of the shell and a floating ormovable header construction contained in the other end of the shell.

As is well known, the purpose of this type of apparatus is to transferheat from one fluid to another fluid, one fluid being circulated throughthe interior of the tubes andthe other through the shell and contactingwith the exterior surface of the tubes.

The purpose of the floating head type of heat exchanger is two fold,first to permit removal of the tubes and tube sheet lengthwise of theshell, and a second, to provide for relative expansion of the tubes andshell which may be due either or both to different coefiicients ofexpansion of the metals of which the shell and tubes are made, and tothe difference in temperature between the fluid passing through thetubes and the fluid passing through the shell.

It is recognized that the most eflicient operation in heat-exchangers isobtained wherein the tubes come closer to filling the entire interior ofthe shell, the fluid passing through the shell having a tendency totravel the line of least resistance which is through spaces between thetubes. In order that the floating tube sheet be removed through theshell, the diameter of the tube sheet must, of course, be less than thatof the shell. Also, in order that the tubes fill as near as possible theinterior of the shell, openings for the tubes in the tube sheet must beplaced as near as possible to the periphery thereof. The securing meansfor the floating tube sheet and its header must, therefore, require theminimum of surface on the periphery of the tube sheet.

In apparatus of this character heretofore known to me, it is commonpractice to provide partitions in the headers to divide the latter intotwo or more chambers so as to cause the fluid in the tubes to passthrough the shell a plurality of times before leaving the apparatus. Forexample, partitions may be placed in the headers so that the fluid firstenters a chamber in'the fixed header and passes through a firstfs'et oftubes to a chamber in the floating header cbmmunicating with the ends ofthe first set'and also with the ends of a second set of tubes, returnedby thesecond set of tubes to a second chamber in the fixed header whichalso communicates with a third set of tubes through which the fluidflows to a second chamber in the floating header which latter is alsoconnected to a fourth set of tubes through which the fluid is conductedto a third chamber in the fixed header and from there to an outlet. Thistype of construction is known as the four-pass type because the fluid inthe tubes passes through the shell four times before it leaves theapparatus.

From the above, it will be seen that for a fourpass type, two partitionsare necessary in the fixed header to provide the three chambers and onepartition in the floating header to provide the two chambers. Morespecifically, the present invention has to do with apparatus of thistype wherein two or more chambers are provided in the floating header.Hence, the present invention is applicable to heat exchangers havingfour or more passes.

It has also been suggested heretofore to provide a longitudinallyextending baflie in the shell so as to provide for a more intimatecontact between the fluid in the shell and the exterior of the tubes.Heretofore in heat exchangers having a floating head and a horizontalbaflie, the common practice is to provide a battle which is removablewith the tubes and tube sheet. however, does not operate as eflicientlyas is desired, due to the inability of sealing effectively the spacebetween the longitudinal edges of the baffle and the shell, and thisresults in the fluid in the shell short circuiting or passing around theedges of the baflie instead of following its proper path through theshell. A further disadvantage of this type of construction, which isalso true of heat exchangers not having the longitudinal bafiie, is thatit often develops that the temperature of certain of the tubes is muchgreater than that of other tubes, thereby .causing the hotter tubes toelongate more than the cooler tubes and placing strains on the movabletube sheet and the joint between the tube ends and movable tube sheet.

Therefore, a more specific object of the present invention is to providea multiple-pass heat exchanger of the floating-head type wherein theplurality of chambers are provided in the fioating head by dividing itstube sheet into separate and independently movable sections with aseparate cap or header secured to each section of the tube sheet by ameans which permits free relative movement between the sections and atthe same time provides for the placing of tubes closely adjacent theperiphery of the tube sheet so as to effect the desired distribution oftubes in the shell.

These and other objects will be effected by my invention as will beapparent from the following paratus taken on the line IIIIII of Fig. 1;

Fig. 4 is a transverse sectional view taken on the line IVIV of Fig. 1and. showing the partitions in the fixed header;

Fig. 5 is an end view of the floating-head end of the apparatus with theshell cover removed;

Fig. 6 is a detail view of the clamping rims;

Fig. '7 is a fragmentary sectional view taken in the same plane as Fig.1 and showing the floating head end of the apparatus, certain of theparts being expanded to indicate their manner of assembly;

Fig. 8 is a view similar to Fig. 7 showing a modified form of myapparatus; and,

Fig. 9 is a view similar to Fig. 5 showing the -modifled construction ofFig. 8.

Referring now in detail to the -construction illustrated andparticularly to Figs. 1 to 7, inelusive, the reference numeral 10indicates a cylindrical shell which may be formed as a seamless tube,and is provided at the opposite ends thereof with flange portions 11 and12 welded to the outer surface ofthe shell and is divided longitudinallyinto a pair of chambers 13 and 14, respectively, by a longitudinalbaille 15 extending for the width of the shell and welded along itsedges to the shell as indicated at 16 (see Fig. 2). The shell 10 isprovided with an inlet opening 1'? for the fluid which passestherethrough and contacts with the exterior of the tubes as willpresently appear. An outlet opening 18 is provided at the end of theshell adjacent the inlet opening and provides for the discharge of p thefluid from the shell.

A plurality of. tubes 19 extend'longitudinally through the shell asshown and connect a fixed header 20 at one end of the shell with afloating header 21 at the other end. Thefixed header comprises a body22, tube sheet 23, end cover 24. The tube sheet 23 is provided withopenings 25 I withinwhich the adjacent ends of the tubes are fixed. Thebody 22 is provided at one end with a flange 26 which engages the outersurface of the tube sheet 23. The header 20 is secured to the end of theshell by bolts 27 passing through registering openings in the flange 26,tube sheet 23, and flange 11. The opposite end of the body 22 isprovided-with a second flange 28 to which is secured by suitable bolts29 the cover24. The

interior of the header is divided into three chambers, 32, 33 and 34, bya pair of partitions 30 and.31(see Fig. 4). An inlet opening 35 isprovided in the body 22 and communicates with the chamber 32 and anoutlet opening 36 isalso provided in the body and communicates with thechamber 33. 55.

The opposite end of the shell 10 is closed by an enlarged cylindricalend portion 37 having a flange 38 welded to the open end thereof. The

I flange 38 abuts the flange 12 on the end of the shell and is securedthereto by suitable bolts 39.-

- The cylindrical end portion 37 is of larger diameter than the shell 10so as to provide an en- 40 which is of smaller diameter than that oftheshell 10 to permit it's withdrawal through the' shell with the tubes.The tube sheet 40 is provided with openings 41 within which the ends ofthe tubes are rigidly secured. The tube sheet 40 is divided into aplurality of sections 42 and 43 which are semi-circular as indicated inFigs. 3 and 5. A cap or cover 44having a peripheral rim portion 45 issecured to the section 42 at the side thereof opposite the tubes andprovides therewith a chamber 46 communicating with the ends of a portionof the tubes 19. The cover 44 is secured to the section 42 by means of asemicircular clamping rim 47 (see Figs. 3 and 6), engaging andoverlapping the arcuate portion of the peripheral surface of thesection42 at the side opposite to the cover 44, and bolts 49 extending throughregistering openings in the rim '47 and cover 44. Bolts 49a serve tosecure directly the second clamping rim 51 and bolts 52 in the same'manner as just described in connection with the cover 44 and section 42.Bolts 52a secure the cover 50 and section 43 along their straight sides.The cover 50 and tube sheet section 43 definea chamber 53 communicatingwith the ends of a portion of the tubes 19. In Fig. 7, I haveshown thecover 50, rim 51 and end portion 37 as expanded so as to more clearlyillustrate the manner of attaching the covers to their respective tubesheet sections.

The baffle '15 lies in the same planeas the line of division between thetube sheet sections 42 and 43 and, as shown, may extend between thesections.

From the above, it will be apparent that, by removing the end portion 37and the covers 44 and 50, and rim portions 47 and 51, the floating tubesheet 40 may be withdrawn lengthwise through the shell, the section 42passing through the chamber 13 and the section 43 passing through thechamber 14.

In order to provide more intimate contact 1 successive passages 63 inthe chamber 13, through openings 66 in the baffle 15 and then throughsuccessive passages 63 in the chamber 14 to the outlet opening 18. Thearrows in Fig. 1 show the passage of the fluid through the shell.

Thebaffles 60 and 61 are tack-welded to longitudin'ally-extendingspacing rods 67 so as to assure; tgeir relative position in the shell.The bafiles' 6 removed with the tubes.

The fluid which flows through the tubes 19 is admitted through the inletopening 35 to the chamber 32 in the flxed header 20 and flows through afirst set of tubes which communicate with the chamber 32, to the chamber46 in the floating header 21. The chamber 46 is alsoin communicationwith a second set of tubes and the fluid is returned thereby to thechamber 34 and 61 and the spacing rods 67 are Communication 1,990,251,in the fixed header 20. The fluid is returned .14, the fluid passingfrom chamber 13 to chamber 14 only through the openings 66. Furthermore,by dividing the floating tube sheet into sections with the line ofdivision in the same plane as the bafile, the tubes and tube sheetsections may be readily removed without disturbing the baflie. The rimclamping feature for securing the covers 44 and 50 to their respectivetube sheet sections 42 and 43 provides for the placing of the tubesclosely adjacent the outer periphery of the,

tube sheet and consequently for the proper distribution of the tubeswith respect to the shell. A further and very importantfeature of myapparatus is in the fact that each tube sheet section and its respectivecap is freely movable longitudinally of the shell without interferingwith the other section and cap. This latter permits free ,relativeexpansion between the tubes secured to one section and those secured tothe other section and thereby reduces the degree of strain placed on thetube sheet and the joints between the tube sheet and tubes. This featureis especially advantageous in constructions employing a longitudinalbaffle, as there is usually a large difference in temperature betweenthe fluid entering the shell and contact with the tubes at one side ofthe bafile and the fluid leaving the shell and contacting with the tubesat the other side of the baflle.

In Figs. 8 and 9, I have shown a slightly modified form of constructionfor the floating end.

As will be observed, I provide a tube sheet '70 divided into sections'71 and 72 and these sections are closed respectively by covers 73 and74. The covers 73 and 74 have arcuate portions 85 similar to the coversof the previously described modification, but are formed differentlyalong their adjoining sides in that they are provided with serratedportions 75 and '76 which interfit with one another. The arcuate edgesof the covers '73 and 74 are secured. to their respective sections 71and 72 by means of arcuate rims '77 and '78 and. bolts 79 in somewhatthesame manner as the corresponding parts of the previously describedmodification. The adjoining edges, however, of the sections 71 and 72are secured to the diametral portions "of their respective edges bymeans of bolts 80 extending through holes 81 provided in I theirrespective caps, and provided'hook portions 82 engaging the side of thesections opposite to the caps, the bolts serving f to clamp the sectionsto thecap. By reason of this construction, the

'bolts 80 may be arranged in. a straight line, as

shown in Fig. 9, and, therefore, a minimum portion of the surface of thetube sheet sections is required for the securing of the caps thereto.

While I have shown my invention in several forms, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various other changes and" modifications, without departing from thespirit thereof, and I desire, therefore, that only such limitationsshall be placed thereupon as are imposed by the prior art or as are"specifically set forth in the appended claims.

What I claim is:

i. In heat exchange apparatus of the fioatinghead type, the combinationof a tubular shell; a tubular end construction having larger ,transversedimensions than the corresponding dimensions of the shell; a tube bundlein the shell; a

tube sheet for one end of the tube bundle and respective section so asto provide for relative longitudinal movement of sections; eachmeanscomprising a rim element engaging and overlapping at least a part of theouter periphery of its respective section at the side opposite therespective cap, and bolt means connecting the rim and cap, the adjoiningedges of said caps being formed as interfitted serrations and; for thisportion of the capsa substantially straight line of bolts being used forsecuring directly the cap to its respective tube sheet, the arrangementbeing such that alternate bolts secure together the same tube sheetsection and its respective cap.

2. In heat exchange apparatus of the floating head type, the combinationof a tubular shell having a baffle fixed thereto and extendinglongitudinally thereof; a bifurcated tube bundle arranged in the shellwith portions thereof disposed at either side of said baflie; theportions of said tube bundle having segmental tube plates such thatopposed chordal edges thereof are disposed at either side of the bafllewith the arcuate peripheral edges thereof capable of being movedlongitudinally within the shell; a segmental head construction for eachsegmental tube plate and embodying a header comprising a segmental rimportion having its ends joined by a chordal rim portion with a platejoined to the rim portions to form an enclosure, said arcuate andchordal rim portions being adapted to fit against the arcuate andchordal margins of the associated segmental tube plate, an arcuate ringsection adapted to align with the arcuate rim portion with the arcuateedge of the associated tube plate segment therebetween, an arcuateseries of bolts for connecting the arcuate rim portion and the arcuatering section so that the latter may bedrawn together to grip the arcuateedge of the tube plate segment, and a chordal series of bolts extendingthrough the chordal'rim portion and threaded to the chordal margin ofthe associated tube plate segment; and means connected to one end of theshell and forming an enclosure for the head constructions providing formovements of the latter incident to expansion and contraction of thetube bundle. i

'3. A heat exchanger having at least two shell passes and at least twotube passes in each shell outlet chamber, a fixed tube sheet adjacentsaid header construction, a longitudinally-extending bafile fixed in theshell and forming a partition between two shell passes, tubes. extendinglongitudinally in said shell passes and secured at one posed on theinner side of the arcuate marginal portion of each floating tube sheetsection, means for securing the arcuate ring sections to the respectivearcuate rim portions of said covers with the arcuate edges of thefloating tube sheet sections secured therebetween, means for securingsaid chordal rim portions of said covers and the chordal marginalportions of said floating tube sheet sections together, and a closurefor said other end of the shell, said inlet, outlet, and reversingchambers being arranged to provide an even number of tube passes in eachshell pass.

4. A heat exchanger as specified in claim 3, wherein each segmentalcover is formed on a radius greater than the radius of the interior ofthe shell.

5. A heat exchanger as. specified in claim 3, wherein the means forsecuring said chordal rim portions of the covers and the chordalmarginal 7 portions of the floating tube sheet sections togethercomprises bolts threaded directly into said tube sheet sections. v

6. A heat exchanger having at least two shell passes and at least twotube passes in each shell pass, and comprising a shell, a fixed headercon- "struction at one end thereof providing an inlet chamber, areversing chamber and an outlet chamber, a fixed tube sheet adjacentsaid fixed header construction, a longitudinally-extending baffle fixedin the shell and forming a partition between the two shell passes, tubesextending longitudinally in said shell passes and secured at one end tosaid fixed tube sheet, a floating tube sheet section secured to theother end of the tubes in each shell pass, said floating tube sheetsections being of a size to permit longitudinal movement thereof throughthe respective shell passes, a cover, secured to each floating tubesheet section to form therewith a reversing chamber and having rimportions engaging the outer sides of the margin portions of the tubesheet section, a retaining member extending along the inner side ofthemarginal portion of each floating tube sheet section which isadjacent the shell, bolts ex tending through said retaining members andthe respective rim portions of said covers for securing the sametogether with the edges of the floating tube sheet, sections securedtherebetween, bolts extending through the rim portions of said coverswhich are adjacenteach other and threaded directiy to the respectivemarginal portions of the floating tube sheet sections'for securing thesame together, and a closure for the other end of the shell, said inlet,outlet, and reversing chambers being arranged to provide an even numberof tube passes in each shell pass.

. JOHN A. POTTER.

